Here’s a list of add-ons to include Bing as your search provider in your browsers & Win7. Though the rollout is not complete in all countries, it would be better you change your country preferences to US in order to experience the Bing. This guide collates how to add Bing in:

Why should Opera miss out on the part? That doesn’t sound fair..so here it is :
Go to http://www.bing.com. Right click on the search box and select Create Search option from the rt-click context menu. Enter a desired name and shortcut and you are all set.